1. Okayama University, Okayama, Japan
2. Graduate School of Information Science and Tech-nology, Hokkaido University, Sapporo, Japan
3. Chubu Electric Power Company, Nagoya, Japan
4. Research Center for Nuclear Physics, Osaka University, Osaka, Japan
5. National Institute for Materials Science, Tsukuba, Japan
6. Department of Electrical Engineering and Bio-science, Waseda University, Tokyo, Japan